RELATED APPLICATIONS
There are no applications related hereto heretofore filed in this or any foreign country.
1. Field of Invention
This invention relates generally to rotary mixing apparatus, and more specifically to such an apparatus that is peripherally defined by elongate cylindrical elements that have substantial cross-sectional area perpendicular to their rotational direction to create turbulence upon rotation.
2. Background and Description of Prior Art
Apparatus moved by a powered rotating shaft has long been known for mixing fluidic, semi-fluidic (viscous) and quasi-fluidic (containing solid particles) materials to form a more homogenous mixture. Such apparatus has taken many and various forms determined primarily by the configuration of the mixing apparatus, the nature of the material being admixed and the rotational speed of the apparatus. Though the historical developmental period of such mixing apparatus has been long and throughout that period the apparatus developed has become increasingly sophisticated, problems still remain with such apparatus, and especially in any generic type of apparatus that well and efficiently mixes both low viscosity fluids and more highly viscous semi-fluid and quasi-fluid materials. The instant device provides a mixing apparatus, usable in a wide variety of materials and through a wide range of rotary speeds, with substantial efficiency.
Rotary mixing apparatus may be divided into two generalized classes for ease of consideration, with a first class comprising devices intended to mix more fluidic materials generally at relatively higher rotary speeds and a second class intended to mix more viscous semi-fluidic material or quasi-fluidic material containing particulate matter at slower speeds.
The first class of mixing apparatus generally provides a plurality of interconnected elements, usually of circularly symmetrical array and generally of smaller cross-sectional area in a plane perpendicular to the direction of rotation than do mixing devices of the second class. Such configuration allows more rapid rotation of the mixing apparatus without excessive force on any of the rotating elements and allows sufficient rotary speed to create a vortical type configuration in a fluid being admixed without ejecting the fluid from a container that is not of substantially greater volume than the fluid. The vortical type action of such mixers is considered by most users to provide a better and more rapid mixing of the components of a mixture to create a homogenous product. Such mixers, however, are not practical or efficient for mixing viscous semi-fluidic material or quasi-fluidic material containing particulate matter, as their structure is not strong enough to allow rapid rotation and the size of the mixing elements is not great enough to create sufficient material friction and motion for proper mixing. Additionally this first class of apparatus generally has a circularly symmetrical structure to promote rotation at higher speeds without excessive vibrations which normally cannot be completely restrained and this, especially when coupled with small cross-sectional size of the elements, further reduces the efficiency of mixing of viscous material.
Rotary mixers of the second class generally are rotated at lower speeds and present cross-sectional patterns of greater areal extent in a plane perpendicular to the direction of rotation of the mixer, so as to create motion in the material adjacent to the mixer elements relative to the material spacedly adjacent thereto which causes motion in the relatively moving portions of material to more efficiently and effectively accomplish the mixing function.
Generally the members of this second class of apparatus have provided flat blade-like elements, often particularly shaped to aid their function, that are of substantial area. Such blade-like elements often are angulated to a plane perpendicular to their direction of rotation to allow rotation at a higher speed and to direct the motion of material impinging thereon in a more efficient mixing action. Since these devices rotate at relatively slower speeds than apparatus of the first class, it is not necessary that they be of so symmetrical a nature as higher speed devices of the first class and often an asymmetrical configuration has been used to enhance the mixing action of the second class of mixing apparatus.
The instant device combines features of both the first and second class of mixing apparatus described to provide a new mixing device that functions equally well at higher speeds in more fluidic, lower viscosity materials and also at slower speeds in more viscous semi-fluidic and quasi-fluidic materials.
To accomplish these ends a mixer structure formed of interconnected areally larger rod elements of circularly symmetrical array is provided. The rod elements are spatially arrayed so that when the structure is rotated some elements move in each of three mutually perpendicular planes to maximize their mixing function. The cross-sectional size of the elements in a plane perpendicular to their direction of rotation is substantially greater than that of wire-like elements that have heretofore been used in rotary mixing devices for fluidic material of low viscosity. The instant elements allow the mixing of low viscosity fluids at speeds that create a vortical motion and tend to enhance that mixing by the creation of greater fluidic friction and turbulence about the interface of the moving elements and fluid being mixed with greater motion of the fluid surrounding the moving elements relative to the fluid more distant therefrom to accelerate and make more efficient the mixing action. The mixing action is also enhanced at lower rotary speeds in more viscous mixtures where the curvilinear shape of the moving elements allow higher speeds than normally attained in prior viscous material mixers, so that the mixing action of the larger surface and cross-sectional areas and higher rotary speeds synergistically combine to provide a more efficient and rapid mixing action for viscous materials.
My invention resides not in any one of these features individually, but rather in the synergistic combination of all of the structures of my mixing device that necessarily give rise to the functions flowing therefrom.